Carbonization process and apparatus therefor



Aug. 5, 1930. F. c. GREENE ET AL 1197533399 CARBON]:ZA'I'ION PROCESS AND APPARATUS THEREFOR Filed Sept; 18, 1924 it C Greene;

' Fran iPatented Aug. 5, 1930 'lTED- STA PATENT- OFFICE.

seams c. GREENE, WA'UKEGAN, ILLINOIS, AND IRVI G- 1'. LAUoKs, or SEATTLE, WASHINGTON, ASSIGNORS TDOLD BEN COAL CORPORATION, or CHICAGO, ILLINOIS,

CORPORATION OF DELAWARE Application filed September 18,1924. Serial No. 738,326.

This invention relates generally to the coking of coal and in particular to coking coal in a retort having a screw conveyor.

In the coking of coal, therotary screw conveyor is a desirable structure which heretofore has met with little or no success in practice. Considering generally a coking process in such a retort, the coal is advanced through the retort producing three zones; first, the granular zone in which the coal is heated; second, the plastic' zjone in which the hot coal becomes agglomerated into a sticky mass, sometimes almost liquid, and thirdly, the setting zone in which theplastic material begins to solidify'for the formation of coke. Throughout all these stages volatile matter is eliminated, permitting the change in character from the granularstate to the coke. It has heretofore been found that in the plastic zone the material adheres to the rotor to such an extent that a retortof this character generally clogs, making it difficult to operate without the use of heavily constructed apparatus and a tremendous driving force. Because of these operating difiiculties, it is advisable to shorten the length of the plastic zone in order to make more practical a retort of. this character. However, it is more desirable to lengthen the plastic zone in order to control the character of the products eliminated in the carbonizing process.

Consequently, it is desirable in lengthening the plastic zone to providesome means or method which will overcome the sticking tendency of the coal to the rotor, thereby eliminating the operative difficulties. One method by which sticking of the plastic coal to the rotor maybe avoided is by the use of a heated rotor, heat being so applied .to the rotor that in the plastic zone it is at least as hot and preferably hotter than the temperature of the retort walls at the opposite points. This method has been found operatively successful in reducing friction or adherence of However, there is one disadvantage in applying this method for this purpose, since when it is desired to lengthen the plastic zone the means employed for the purpose introduce an additional quantity of heat to the retort, thereby tending to hasten the process and to shorten the plastic zone. It is therefore desirable that other means or method be employed aside from the heated rotor. One of the effects of theheated rotor in eliminating adherence of plastic coal is due to the generation of agas at the interface of the rotor and the coal. The effect of the gas is to form a film or cushion between the coal and the rotor to reduce the area of the material in direct contact with the rotor, thereby favoring selective adhesion of the coal to the retort wall in preference to the rotor wall. The manner of doing this is the formation of bubbles in the highly plastic coal and by the formation of an elevating layer of gas in the more nearly solid coal, the escape of the gas from the interface elevating the material from the rotor.

it is the object of this invention to coke coal in a retort having a screw conveyor by producing a similarly functioning film or layer at'the interface of the coal and the rotor in any other practical manner, in distinction from utilizing the decomposition of the coal as v a source of the material forming the cushioning film;

It is a particular .object of the invention to introduce at the interface of the coal and the rotor a suitable substance which will prevent or minimize adherence of the coal to the rotor.

It is another object of the invention to maintain a supply of such a suitable substance Within the rotor for introduction at? the interface. Still another object is the provision of a rotor of a type suitable for maintaining such a supply, and furthermore to/provide a construction associated with the rotor for maintaining the supply from an external source if desired.

It is another object of the invention to production of a suitable cushion by its decomposition along with the coal.

Other and ancillary. objects and advantages will appear hereinafter,fr0m the description of a particular construction, shown Fig. .3 1s a cross-section of the-rotor on the line 3--.3'of Fig. 1.

Fig. 4 is an enlarged detailed view of a- \portion of the cross-section of the retort on line 3-3 of Fig. 1.

In the drawings we have chosen to illustrate the invention as embodied in-a coking retort having'a continuous feed of coal therethrough from the bottom to the top. In such a retort the movement of the coal upwardly is naturally retardedby friction or sticking to the rotor. In ordinary coking practice such a retort will clog and be inoperative primarily because of. the stickiness. It is 1 commercially desirable to decrease the friction or sticking, in order to be able to feed a considerable quantity of coal through the coking zones in arelativelyshort time.

The retort in general comprises a cylindrical chamber 5 of any desired construction.

and preferably slightly flaring in the direction of passage of the coal.v .Suitable means for heating the retort are diagrammatically represented by the combustion space 6 surrounding the retort. The retort 1s shown as suspended from suitable supports 7 and 8 by an enlarged cooperating tapered head 9 on the retort.

Upon an annular base 10 beneath the lower end of the retort is supported a cylindrical -rotor 11 having helical, ribs'or flights 12 thereon arranged to .fill the inside of'the tapered retort 5, a snu fit being provided. The rotor 11 extends t rough the retort at the top for operation by any desirable power means (not shown). Both'ends of theretort are suitably closed off. The lower or feeding end has a casing 13 thereabout ex.- ternal to the retort. Means for feeding coal to the retort and means for withdrawal of vapors, are associated with the casing.

The casing 13 is substantially annular in form supported at 14 o'nthe base 10, and

sealed by packing 15'at the top about theretort, which is thereby free to expand and contract. Suitable vapor exits 16 are con structed near the top of the casing, one of which is utilized by the vapor pipe 17. Other openings 18 are provided for feeding means. The opening 18 atthe right of the Figs. 1 and 2 has a pipe 19.0onnected thereto containing a feed screw 20 for introducing coal onto the floor 21 of the casing, whence it is carried upwardly into the retort by the rotor flights 12. The bottom of the retort wall 5 extends close to the' floor 21 and at the end is provided with suitably long openings 22 which permit the escape of vapors to the upper part of the casing.

The sealing means at the upper end comprise a chamber formed by the supports 7 and 8 and by a suitable liquid seal. An annular ring 23 is rigidly mounted with reference to the supports, said ring having a vertical cylindrical portion 24 projecting down wardly. The rotor 11 carries an annular channel member 25 into the channel space of which a liquid 26 is placed. The part 24 dips into the liquid to effect the seal. A suitable inclined passage 27 is provided to carry ofl the char delivered'by the rotor.

Vertically through the rotor in the casing thereof are ducts 28 communicating with the retort chamber in the so-.called plastic or sticking zone of the retort. Circular slots .or

ports 29-radially cut into the rotor constitute the means of communication in the present instance. The slot covers about one-half the Space between the flights and also a considerable portion of the flight itself, forming a cup-shaped portion 30in the rotor. In Fig. 4 the direction of rotation is indicated as clockwise by the arrow 31. The rear side of the slot 29 is cham fered at 32 in the flight and at 33 in the: rotor. The ducts 28 extend through the rotor "at the bottom, having the angular portion 34. A supply pipe 35 is arranged beneath the support 10 and communicates therethrough in a series of pipes 36. Bearing rings of metal 37 and of fibroid 38 are interposed between the base 10 and the rotor 11. Holes 39 through said rings serve to connect the pipes 36 to the rotor channels 34. Suitable lubricants or cushion forming substances are thus introduced from the. supply pipe 35 to the rotor flights directly. Optional means are shown at 40 in the pipe 19 for introducing some suitable material into the retort with the coal itself.

As to the manner of producing a lubricatin cushion, various substances are available or choice. For example, oil as a lubricant may be introduced, its character bein such that it is not completely destroyed by the temperature of the sticking zone, or

otherwise, its supply being sufiicient to efi'ect lubrication. Graphite may be introduced in the powder form by a stream of conveying gas, the graphite being a mechanical lubricant, and the gas forming a suitable cushion between the charge and the rotor. A gas under pressure may be admitted to gaseous film under the material to minimize the sticking. Petroleum residues may be added and the char resulting therefrom removed with the coke derived from the coal. In the latter case where a considerable quantity of petroleum may be added, it may be desirable to mix the same with the charged .coal by addition through pipe 40. I With reference to the last named substance form a sult in a mixture of volatile products derived both from the coal and from the petroleum, and when such a mixture is desirable, the apparatus will provide a valuable and practical continuous process for the cracking of oil, the

coke ,formed from the coal serving as a vehide to remove the char and residue left by the cracking process. Carrying the combination ofoil cracking-and coal carbonization one step .further, the process herein disclosed maybe effectively employed as a cracking process without regard for the coal carbonizing. In place of using a carbonizing coal I which will enrich the volatile products from the petroleum with volatile products from the coal, a non-volatile coal or coal dust, or coke breeze may be employed as the vehicle to carry the oil and the char therefrom through the retort, thereby giving a continuous process for the cracklngof oil, and the utilization of Waste products.

Although the above described means and the above named substances all contribute to the formation of a cushion effect between the charge and the rotor, the disclosure of such means and the substances, and the disclosure of the various processes derived from the use thereof, are merely for the purpose of illustrating and explaining the invention. The matter above set forthis not to be construed as limiting the scope of the invention which is set forth and defined by the appended claims.

We claim as our invention 1-. A. retort for coking of carbonaceous material comprising, in combination, an elongated circular chamber, means to heat said chamber, a rotor in said chamber, helical prising, in combination, an elongated circular retort, means to heat said retort, a screw conveyor in said retort, means to feed carbonaceous material'to said conveyor, and means to feed other material through the conveyorto produce a cushion between-the flights of the conveyor and the carbonaceous material, said means including ports which open upon the flights.

3. A coking retort comprising, in combination, an elongated circular chamber, heating means therefor, a rotor in said chamber, conveying flights on said rotor, a duct within said rotor, the external wall of the rotor having holes therethrough communicating with said duct, said holes being substantially at the junction of the rotor wall and the flights at the material supporting side ofthe flights, and means to communicate with the duct from a point external of the retort for discharging fluid under pressure upon the material-supporting side of the flights.

4:- A coking retort comprising, in combination, an elongated circular chamber, heating means therefor, a rotary conveyor in the chamber having helical flights for passing material through said chamber, said flights extending substantially to the walls of said chamber means-to feed raw material to be coked to said flights, means in said rotor to feed a cushion-forming substance to the flights, and means to feed the substance to said means in the rotor.

5. Acoking retort comprising, in combination, an elongated circular chamber, heating means therefor, a rotary conveyor in said chamber having helical flights thereon, means to feed material to be coked into the chamber, a plurality of ducts within the conveyor longitudinally thereof, means to feed asuitable substance into'said ducts, and a plurality of holes in the conveyor above said flights communicating with said ducts.

6. A vertical coking retort comprising, in

combination, an elon ated circular chamber,

e provision of a sup- 1 7. A vertical coking retort comprising, in

combination, anelongated circular chamber, heating means therefor, a rotary conveyor in said chamber having helical flights thereon for conveying the material being treated up and out of said-chamber, means to provide a supply of cushionin material in said rotor, and means for intro ucing said material onto the rotor surface at the interface thereof with the coal to facilitate the sliding action there-- between; I 8. A verticalcoking retort comprising, in.

combination, an elongated circular chamber,

tion of rotation of the rotor, being chamfered. 1

9. In a coking retort, a screw conveyor combination,

having helical fli hts, means permitting the provision of .a In ricant supply within said conveyor, a plurality of slots through said conveyor wall to the lubricant supply, said slots being in the shape of a circle intersecting the supply and cutting into the conveyor.

flights, one side'of each slot being chamfered in the conveyor wall and the flight.

10. a coking retort, a screw conveyor having helical fli hts, means permitting the provision of a In ricant supply within said conveyor, a plurality of slots through said conveyor wall to the lubricant supply, said slots being in the shape of a circle intersectiinglthe supply and cutting into'the conveyor -11. A coking retort comprising in combination, avertical elongated chamber,'-means to heat said chamber, a screw conveyor there'- in having helical flights, means 'at the bot-- tom of the chamber to feed material to be coked onto said' flights, means at the top of said chamber for receiving the coked material, meansfor withdrawing gas, and means flqr iiptroducing a cushioning substance onto t e i thereo with the material the retort.

12. A vertical retort comprising, in com bination, an elongated circular chamber tapering toward the bottom, heating means i H therefor,:a casing at the bottom closing said chamber, means to feed coal to the retort through said casing, a screw conveyor in the chamber to carry the coal to the top, exit means for the coked coal at the top, meansv for the withdrawal of vapors associated with the casing at the bottom, and means to introduce a cushioning substance onto the flights of the conveyor to facilitate passage of the coal through the heated zone of the retort.

13. A vertical coking retort comprising, in an elongated circular chamber, means to suspend said chamber, a rotor in said retort, means to support said'rotor at the bottom thereof, a casing about the lower ends of said chamber and said rotor, means associated with a casing to seal the end of the chamber, coal. feeding means in said casing, means permitting the provision of a supply of cushion-forming material for said rotor, ducts in said rotor to receive the supply, and communicating means from the rotor to the rotor-'sup'porting-means whereby to supply the material to said ducts.

14. A coking retort comprising, in 'combination, an elongated circular chamber, a rotor therein, a base to support said rotor at the bottom, bearing rings between said rotor and said base, a duct in said rotor opening at the end thereof, means permitting the provision of a supply of cushion-forming material,

communicating means through said base, sald base and rotor hts of the conveyor at the interface passing through.

from the supply and rings intermediatehaving holes therein to supply said rotor duct with a cushioning substance during the rotation thereof. a 15. The method of coking coal in a vertical retort provided with a screw conveyor which consists in moving the coal upwardly through the retort on the flights of the conveyor,- heating the retort to coke the coal, and

introducing a lubricant substance onto the flights of the conveyor to produce a cushion effect on the flights at the interface thereof with the plastic coal.

I 16. The method of coking coal in a vertical retort provided with a screw conveyor cal retort provided with a screw conveyor which consists in feeding coal upwardly through the retort, heating the retort, introducing into theretort a liquid etroleum sub- I stance suitable to form a lu bricating and cushioning film between theplastic coal and the conveyor at the interface, withdrawing the vapors, and removing the char produced from the coal and the petroleum substance.

19. The method of coking coal in a vertical retort provided with a screw conveyor which consists in passing coal upwardly through the retort, heating the retort, introducing onto the conveyor a liquid petroleum substance suitable to form a cushion at the surface thereof, to prevent sticking of the plastic coal to the conveyor in the passage therethrough, and removing theproducts formed by the heating.

20. The method of coking coal in a vertical retort provided with a screw conveyorwhich consists in passing coal the retort, heating petroleum product to the coal passing through the retort, the heat serving to volatilize portions of the petroleum and of the upwardly through the retort, adding a liquid coal and forming a char, the li uid of the menses means for heating said chamber to heat sail material in the course of its passage through saicl chamber to a temperature at which it becomes plastic, and. means for supplying a foreign substance to the intertace'of said conveyor in the region in which said material becomes plastic, said foreign substance being introduced'to facilitate theslioling action of the plastic material on said conveyor.

22. The method of coking coalthat will become plastic upon suficient heating ina vertical retort provided wit-ha screw conveyor 7 the sliding action of the plastic coal on the conveyor. c In testimony whereof we have hereunto afixed our signatures.

tilt

FRANK C. GREENE. IRVING F. .LAUCKS. 

